SSL
All webapp type appliances (e.g., Joomla) support SSL out of the box. Just browse to https://appliance_ip
Further more, Joomla has the configuration option to force SSL for the entire site, or only for the administration console

Joomla Administration -> Global configuration -> Server -> Force SSL

Server maintenance
Well, that is quiet an open-ended question. Essentially, all servers need some form of maintenance now and then. We have tried to minimize overhead by configuring all TurnKey appliance to auto-update daily with the latest security patches.

OpenGoo
I was unaware of OpenGoo, but it looks interesting and we will definately take a look, thanks!